Stress corrosion cracking behavior of 310S stainless steel in supercritical water at different temperature

The stress corrosion cracking (SCC) behavior and tensile properties of 310S stainless steel were studied by slow strain rate tensile (SSRT) tests, which were carried out in oxygenated supercritical water at the temperature of 400, 550, and 620 degrees C, respectively. The distribution of chemical composition of oxide, tensile properties, fracture morphology of the materials were analyzed for evaluating the SCC susceptibility of 310S stainless steel, respectively. The results show that both the elongation and tensile strength decreased significantly with the increase of the temperature, implying that a higher temperature may lead to a higher SCC susceptibility. The remarkable changes of the morphology of the fracture surface and gauge surface of 310S stainless steel were observed at different temperatures, that is, from an entire ductile fracture at lower temperature to a brittle fracture at higher temperature. The temperature has significant effects on morphologies and thickness. Oxides with double layer were observed. TEM analysis revealed that the inner oxide layer is composed of Cr and O, and Ni-enrichment can be observed to segregate at the metal-oxide interface.